A number of households have been forced to flee their homes after being flooded for the third time this year.
Rhondda Cynon Taf council said there had been significant flooding to almost 200 properties in the borough after storms swept across Wales on Wednesday.
The village flooded twice during February's storms with the cost of the damage estimated at up to £5m.
Plaid Member of the Senedd (MS) for the Rhondda, Leanne Wood, said people were angry and called for an inquiry.
More flooding is feared later with further thunderstorm weather warnings issued by the Met Office.
Five hours pumping out water
South Wales Fire and Rescue Service said it spent five hours pumping water out of homes in Pentre, near Treorchy in the Rhondda valley.
It said it took 51 calls for help from 18:15 BST on Wednesday and was also called out to properties in nearby Maerdy.
'Angry and frustrated'
Ms Wood said: "People are angry and frustrated that this has happened twice already this year... I share that anger and frustration - it is not acceptable.
"What is needed is urgent assistance from the various authorities to prevent further flooding.
"Sandbags - which were not forthcoming from the council initially - need to be delivered to every home that is at risk of further flooding throughout this spell of heavy rain."
'Why so vulnerable to flooding?'
She said drains needed to be cleans and called for an inquiry to look into "why these areas are so vulnerable to flooding".
"This work should have happened already; even with restrictions around the Covid-19 pandemic," she said.
The storms of Ciara and Dennis had left Wales with an estimated £180m clean-up bill - and with more than 1,000 properties affected in Rhondda Cynon Taff in February. The damage cost the local council about £15m.
Ms Wood had taken to social media to ask for volunteers to help clean up Maerdy Community Primary School after flood water entered the main hall and nursery.
Village hit 'quite badly'
Nigel Williams, from South Wales Fire and Rescue Service, was in charge of the operation on Thursday night and said the Pentre had been hit "quite badly".
"Our hearts and minds go out to people affected by flooding not only this occasion but previously as well," he told BBC Radio Wales Breakfast.
Mair Hughes' home in Pentre was badly hit in February's flooding and was flooded again on Wednesday night.
She said facing another clean up was "heart breaking".
"All the muck again... I was crying," she said.
"With the children in the house as well it's just really bad. Twice in four months."
'Terrible'
Ann Inkpen, who has has lived on North Terrace in Maerdy for 42 years, said: "All of a sudden the water came rushing in the back. It was through the whole house in seconds.
"My elderly neighbours on both sides, who were shielding, have had to move out. It's terrible."
Neighbour Cynthia Mainwaring said: "It was horrendous. It was so much rain.
"Luckily we managed to put towels and paper down - It came through in minutes and then it was gone.
"The damage isn't too bad, I don't think, but it will take some cleaning.
"Lockdown is going to be remembered for some time here."
'Horrible'
Adele Wilk has been distributing cleaning materials to people on North Terrace in Maerdy.
She said: "The council brought stuff like bleach last night and I've been handing it out.
"There's a lot of older people here so I've been knocking their doors checking they're all OK. It's horrible."
Council leader Andrew Morgan said the council had deployed additional resources to support highways crews and help the emergency services dealing with the flash flooding.
He added: "This has unfortunately impacted upon communities which have already experienced the devastation of flooding earlier this year."
One property in Rees Place suffered partial collapse and structural engineers attended.
One Queen Street resident told BBC Wales he was angry at watching his home being flooded again: "I would like to see some of these councillors to live in these houses and go through what we've done.
"I haven't been in this house since February. I've had to go around the corner and live with my daughter."
At the scene: Our reporter Alun Thomas
"More rain in Pentre this morning will be the last thing that residents here will want after last night's downpour.
"The sandbags outside so many houses is a sign of what happened here, while skips standing in some streets show that this is a community still getting back on its feet after the severe flooding back in February.
"For some their renovations were finished yesterday just hours before the rain returned, with the flooding seeming to come from nowhere in a matter of minutes.
"As the clear up - and the rain - continues, this has become a community searching for answers."
Councillor Maureen Weaver, who represents the Pentre ward, told BBC Radio Wales Breakfast: "It was dreadful last night and listening to the weather forecast it's going to be dreadful again…
"We need drains all cleared urgently and an inquiry to see why this is happening."
On Wednesday, a Met Office yellow warning for thunder was in place for 20 of Wales' 22 counties.
Buffy Williams, from Canolfan Pentre Community Hub, said she and others were at the centre until 23:00 BST on Wednesday handing out cleaning products and would be returning on Thursday morning.
She said: "It's a nightmare trying to maintain social distancing with the mess. Thankfully the police and our PCSOs are coming in to help at the centre today."
Another thunderstorm alert is in place for Thursday for all south Wales counties, pushing west into Carmarthenshire and north of Brecon in Powys, between midday and 21:00.
There was also a yellow warning for rain in place from 03:00 until 12:00 on Thursday for all counties except Pembrokeshire, Vale of Glamorgan and Cardiff.